I already have the Karen Winfonstad Atlas of Middle-Earth in my PC... it has some very interesting maps, even climatological and such. But most of it was done based in supositions - thought the best supositions ever, with a lot of research and geografical accuracy.
And Tolkien probably wrote some texts about other places in ME, but his stories were most about the Northwest of ME because the elves lived mostly there. As it's said, Gandalf and the other wizards (except the blue) went there because there lived the last elves, and the peoples that were contacted by them and so freed from the Shadow, so there was more hope of defeating Sauron. (Made me remember the Light of Aman religion... it's more important than I have thought when made the religions...)